The present invention relates to a spacer type pressure reducing valve mounted between a switching valve which switches a direction of flow of pressurized fluid and a base which supplies pressurized fluid to the switching valve, for adjusting fluid pressures out put to a pair of output ports to required pressures.
When a fluid pressure device is actuated by pressurized fluid such as compressed air supplied through a switching valve, it is desired to adjust fluid pressure to be supplied to the fluid pressure device depending upon a set pressure or actuating state of the device.
In such a case, a pressure reducing valve that is a pressure-adjusting valve is usually mounted in a pipe that connects an output port of the switching valve and the fluid pressure device.
However, since a known pressure reducing valve is large in size in generally, if the pressure reducing valve is connected to the switching valve by piping, there are problem that its piping operation is extremely troublesome and large installation space is required.
Especially this problem is prone to be generated when a plurality of switching valves are mounted on a base such as a manifold or sub-plate having a piping port and are used. It is difficult, in some cases, to mount the pressure reducing valve depending upon the number of switching valves to be used.
Thereupon, in order to solve the above problems, there is proposed a spacer type pressure reducing valve that is directly sandwiched and mounted between the switching valve and the base (Japanese Publication Nos. 10-96404, 10-133744 and 10-283037).
This spacer type pressure reducing valve comprises a valve body having substantially the same lateral width as that of the switching valve, a plurality of communication passages which bring communication holes of the switching valve and the base into communication with each other in the valve body, a pressure-adjusting valve hole provided cutting across the communication passages, a pressure-adjusting valve rod inserted in the pressure-adjusting valve hole, and means for adjusting air pressure to a set pressure by cooperation of the pressure-adjusting valve rod. When adjusting pressures in two output ports that are in communication with the fluid pressure device, two spacer type pressure reducing valves are superposed on each other.
In the above spacer type pressure reducing valve, when the pressures in two output ports are adjusted, since it is necessary to superpose and use the two spacer type pressure reducing valves, there are problems that a pressure-reducing portion becomes large in size and the large installation space is required.
The present invention has been accomplished in view of the problems, and it is an object of the invention to provide a compact spacer type pressure reducing valve capable of adjusting pressures in two output ports.
The above and other object and novel features of the present invention will be apparent from description of this specification and accompanying drawings.
To achieve the above object, a spacer type pressure reducing valve of the invention which is disposed between a switching which adjusts an output fluid pressure and which is disposed between a switching valve having one supply communication hole, two output communication holes and a discharge communication hole and a base having a plurality of communication holes corresponding to the above communication holes, wherein this spacer type pressure reducing valve comprises a valve body sandwiched between the switching valve and the base; two pressure-adjusting valve holes formed in the valve body in parallel to each other, and two pressure-adjusting valve rods movably accommodated in the pressure-adjusting valve holes; one supply communication passage for connecting supply communication holes in the valve body corresponding to the switching valve and the base, and two output communication passages for connecting the corresponding output communication holes, and two discharge communication passages for connecting corresponding discharge communication holes; a pressure-adjusting valve seat and a pressure-adjusting valve body formed in one of the pressure-adjusting valve holes and a pressure-adjusting valve rod therein for adjusting the fluid pressure output from one of the output communication passages, and another pressure-adjusting valve seat and another pressure-adjusting valve body formed in the other pressure-adjusting valve hole and a pressure-adjusting valve rod therein for adjusting fluid pressure output from the other output communication passage; pressure-adjusting chambers respectively provided on one ends of the two pressure-adjusting valve rods, and returning chambers respectively provided on the other ends of the pressure-adjusting valve rods; pressure-adjusting pistons slidably provided in the pressure-adjusting chambers; pressure-adjusting springs for biasing the pressure-adjusting pistons toward the pressure-adjusting valve rods; returning springs respectively provided in the returning chambers for biasing the pressure-adjusting valve rods toward the pressure-adjusting pistons; a communication flow-passage for connecting the pressure-adjusting chamber and the returning chamber on the opposite ends of the one output communication passage and the one pressure-adjusting valve rod, and a communication flow-passage for connecting the pressure-adjusting chamber and the returning chamber on the opposite ends of the other output communication passage and the other pressure-adjusting valve rod.
According to the present invention, said pressure-adjusting piston includes a discharge hole for discharging out the pressurized fluid in the pressure-adjusting chamber, and the pressure-adjusting valve rod is provided at its end with an opening/closing portion for opening and closing the discharge hole.
Moreover, said valve body is provided at its end closer to the pressure-adjusting chamber with two adjusting screws capable of independently adjusting resilient forces of the two pressure-adjusting springs, and two pressure gauges for independently detecting fluid pressures of the two pressure-adjusting chambers.
Further, said communication flow-passage comprises a pressure-adjusting passage formed in the pressure-adjusting valve rod and brought into communication with the returning chamber, a pressure-introducing gap formed between the pressure-adjusting valve hole and the pressure-adjusting valve rod for connecting the pressure-adjusting passage and the pressure-adjusting chamber, and a pressure intake hole for bringing the returning chamber or the pressure-adjusting passage and the output communication passage.
According to one concrete embodiment of the present invention, said supply communication passage in the valve body extends through portions of the two pressure-adjusting valve holes, the pressure-adjusting valve seats are formed on positions through which the supply communication passages of the pressure-adjusting valve holes pass.
According to the other concrete embodiments of the present invention, the two output communication passages in the valve body respectively extend through the two pressure-adjusting valve holes, the pressure-adjusting valve seats are formed on positions through which the output communication passages of the pressure-adjusting valve holes pass.
According to the present invention, in the spacer type pressure reducing valve, since the two pressure-reducing portions are integrally disposed in the valve body, the structure can be made compact and the size thereof can be reduced.
Further, since the pressure gauge is disposed in the vicinity of the adjusting screw, the operability of the pressure setting of the pressurized fluid is enhanced.